Three Dimensional Cone-beam Reconstruction of Micro Computed Tomography in the Breast Specimen
Traditionally, the specimen obtained from a breast biopsy can only be examined by a microscope. Although the resolution of microscope is high, it can only examine one thin section at a time. Hence, the microcalcifications next to the observed section may be missed. To solve for this problem, we acquire the specimen by a 3D micro computed tomography (microCT) with electron bombarded charged coupled device (EBCCD). The objective of this study was to implement and evaluate the 3D cone-beam reconstruction algorithms for the breast specimen using microCT. We have reconstructed the projections of specimen by parallel-beam, fan-beam, and cone-beam algorithms. For the cone-beam algorithm, we used the tent Feldkamp-Davis-Kress method (T-FDK) in this research. To evaluate the performance, we computed the coefficient of variation (CV) and contrast in the reconstructed images obtained from a cubic phantom, and analyzed the result by a t-test. From the results, we found that significant advantage of T-FDK over others. For the breast specimen, the microcalcifications can be easily identified in the images reconstructed using the T-FDK algorithm, but not in those reconstructed from the filtered backprojection (FBP). We then displayed these reconstructed images in 3D, and applied a 3D computer-aided diagnosis tool for classifying breast cancer. However, there are still some artifacts caused by these analytical reconstruction methods. For the future work, we plan to apply statistical iterative reconstruction methods in the microCT reconstruction, and expect the statistical reconstruction methods can reduce these artifacts.